Biocides, and in particular pesticides such as fungicides, insecticides and herbicides, are important auxiliary agents for agriculture in order to protect and to increase crops. Depending on the various and often very specific needs a magnitude of actives exist which show very different chemical structures and behaviours. Nevertheless, it is well known from the state of the art that it remains difficult to prepare aqueous solutions of these actives which are exhibiting a satisfying stability, especially if stored at very low or elevated temperatures over a longer period. As a matter of fact, the solutions show a strong tendency to either separate or to form crystals, which makes it necessary to re-disperse the actives in the compositions prior to every application in order to obtain a homogenous product. Due to the fact that in spray equipments, which are customarily used for the application of aqueous formulations of plant treatment agents, several filters and nozzles are present, an additional problem appears which is related to the blocking of these filters and nozzles as a result of crystallizing active compound during the application of aqueous spray liquors based on solid active compounds.
European patent application EP 0453899 B1 (Bayer) discloses the use of dimethylamides derived from saturated C6-C20 fatty acids as crystallisation inhibitors for azol derivatives which can be applied as fungicides. Unfortunately, the dimethylamides suggested in the patent are useful for a limited number of actives. Even in the case of azols and azol derivatives, the ability to inhibit unwanted crystallisation is limited to ambient temperatures, while the products are close to being useless in the case where the solutions have to be used at temperatures of about 5 to 10° C.
The problem underlying the present invention has been to identify suitable new solvents for developing new biocide compositions, allowing preparing products with equal or higher contents of actives than obtainable in the market. The new solvents need to be safe and environmentally friendly and should allow obtaining concentrated biocide compositions (on average more than 25% active matter) regardless of the chemical structure of the biocide. In particular, the compositions should exhibit improved solubilisation power, storage stability and reduced tendency to form crystals for a wide range of biocides within a temperature range between 5 and 40° C. Finally, another object of the invention has been to design emulsifiable concentrates formulations with specific co-solvents and emulsifier systems, providing superior emulsion stability, in particular with respect to opacity and layering.